Method and apparatus for applying viscous or paste material onto a substrate

ABSTRACT

A solder paste or other viscous material screen printing machine in combination with paste or viscous material applicator ( 1 ) device and an adaptor device ( 41 ) in between the reciprocating mechanism for transmitting the pressing forces of the reciprocating mechanism to the applicator device ( 1 ) whilst limiting the downward movements of the reciprocating mechanism to be within acceptable limits, with said adaptor device comprising a pressure receiving member ( 47 ) and to be acted upon by one or more pressing members ( 44 ) of the reciprocating mechanism of the screen printing machine in a downward direction, and piston displacing means beneath said pressure receiving member ( 47 ) which means, in use, is downwardly displaceable together with the pressure receiving member to cause the piston ( 7 ) to be displaced downwardly when said pressure receiving member is acted on by said pressing members and to urge solder paste or other viscous material contained within the reservoir downwardly, and one-way movement enabling means ( 46 ) operatively connecting said pressure receiving member ( 47 ) to said piston displacing means such said one-way movement enabling means ( 46 ) is such as to normally only permit movement of said pressure-receiving member ( 47 ) in an upward direction away from said pressure members; and wherein said pressure-receiving member is biased away from said pressing member so as to be displaceable upwardly to its original position following each downward displacement thereof and release.

[0001] The present invention relates to an apparatus for applying aviscous or paste-like material through apertures in a stencil onto asubstrate beneath the stencil and is particularly suitable for applyingsolder paste onto a board for producing a printed circuit board or forapplying an adhesive or other bonding agent to a substrate via astencil. The present invention also relates to an adaptor device for asolder paste applicator device with a reservoir for the solder paste andis particularly intended to be used with the applicator device of thepresent invention.

[0002] In GB 234137A and in particular in FIGS. 21-24 and 35 thereofthere is disclosed use of a sealing gasket or foil 55 having acontinuous resiliently backed periphery defining an inner aperturedregion through which paste is displaced downwardly onto a stenciltherebeneath. A “shoe” or spacing member 85 is provided around foil 55.Upstream of foil 55 is a higher pressure space 62 separated from a lowerpressure paste space 63 by a plurality of pressure reduction spaces 61,52′ which are provided to reduce the pressure in the paste thereabovenecessary to maintain the characteristics of the paste.

[0003] The above-described known continuous sealing foil with resilientbacking and spacing means has been found to be exceptionally effectiveand advantageous.

[0004] There are also known solder paste cartridges for use in othertypes of paste applicator devices which devices are not entirelysatisfactory and the cartridges comprise an elongate horizontallyextending container of generally rectangular outline having an open topand multi-apertured bottom and in which container a similarlyrectangular pressure member or piston is locatable over the solder pastecontained therein. The piston is downwardly displaceable under theaction of an especially designed pneumatic pressing device and mountedon a solder paste printing machine to urge solder paste contained withinthe container out of the apertures in the bottom of the container intothe known less effective applicator device which does not have thecontinuous foil.

[0005] In FIG. 16 by pneumatic cylinders 80 of U.S. Pat. No. 6,171,399assigned to Novatec S A and in FIG. 1 by pressure source 2 ofInternational Patent Application PCT/GB95/103002 of Ford Motor Company,there are examples of additional motive power means additional to thereciprocating mechanisms of the printing machine needed to expel pastefrom applicator device.

[0006] The present invention relates to an advantageous improveddispensing or applicator device suitable for use with existinghorizontally extending containers or reservoirs or similar containers orreservoirs and also to a new, combined paste container/reservoir andapplicator device which is preferably intended to be disposable afteruse.

[0007] According to a first aspect of the present invention there isprovided an applicator device for abutment by or attachment to thehorizontal and the vertical mechanical displacement/reciprocating meanshitherto for the squeegee blades of a solder paste printing machine orfor other viscous fluid material printing machine, said applicatordevice being for applying paste-like or other viscous fluid material toa surface therebeneath and comprising a body having a through passagewith an upper, fluid inlet extending along the body and having a lower,fluid outlet aperture in its lower region extending along the body witha pressure reduction means between the inlet and outlet for reducing thefluid material pressure, a sealing gasket or foil for peripherallysealing said outlet against a stencil by being pressed against thestencil surface therebeneath with said gasket or foil being formed froma sheet of flexible material with a uninterrupted or continuous,non-apertured outer part extending around the periphery of said outletand surrounding an inner aperture or apertured inner region of saidgasket or foil, and an elongate, horizontally extending reservoir forfluid material formed with or detachably mounted on the upper side ofsaid main body and extending to be in communication with said inlet ofthe main body or having a fluid outlet or outlets at and along its lowerside in communication with said inlet of the main body, and adisplaceable piston extending in said reservoir for displacing fluid outof said reservoir or outlet or outlets of the reservoir and into thefluid inlet on the main body and then via the pressure reduction meansto the outlet defined by said sealing gasket or foil; said piston beingaccessible or actuable from above by one or more mechanical pressingmembers connectable to or abuttable to said mechanicaldisplacement/reciprocating means of the printing machine for thepreviously removed squeegee blades so as to be displaceable thereby andsaid applicator device being without and not requiring any otherseparate motive power source for such displacement or not requiring anypipe ducting means for any such displacement motive power source (e.g.without any dedicated pneumatic or hydraulic displacement means) otherthan to receive mechanically transmitted displacement forces from saidmechanical displacement/reciprocating means of the printing machine.

[0008] The applicator device of the invention is primarily intended tobe used on a solder paste printing machine which normally has orhitherto had two squeegee blades for sliding on the metal stencil andmounted on two alternately upward/downwardly reciprocable pusher membersor yokes supported by a vertical or reciprocating mechanism which itselfis horizontally reciprocable on a carriage. The squeegees are removedfrom the yokes and replaced normally by two elongate pusher blades whichalternately act on the displaceable piston of the elongate pastereservoir, preferably via a pressure distribution plate which spreadsthe pressure across the piston transverse to its direction of extensionto minimize any backwards/forwards tilting movement of the piston. (Insome printing machines, only one upwardly/downwardly reciprocatingmember is provided and the applicator device can be suspendedtherefrom.) It is envisaged that the pusher blades, for example by beingcurved or cam mounted or otherwise rocking, to cause an alternatetilting displacement of the piston along its length i.e. from side toside, in addition to pressing down and such sideways rocking or tiltingis provided to improve/maintain the characteristics of the solder paste.

[0009] Thus, the present invention in this first aspect also includessuch a solder paste stencil printing machine in combination with anapplicator device according to the invention. It is to be appreciatedthat in such a combination, the force exerted by the pusher plates toexert a pressure and driving force not only horizontally reciprocatesthe applicator device and reservoir over the surface of the stencil butalso exerts a downward pressure on the displaceable piston so as toprovide the pressure to maintain the gasket or foil in sealing contactwith the stencil therebeneath and cause the solder paste to bedischarged from the reservoir and through the apertures in the stencilonto a circuit board or other electronic component or substratetherebeneath. Hitherto, separate displacing means have been provided forthese purposes. It is to be appreciated that the horizontal pressureneeded to slide the applicator device over the stencil and the verticalpressure needed to keep the foil in sealing relationship therewith isapplied via the pusher plates horizontally and vertically via the pusherplates through the paste and is considerably more than necessary todispense the paste through the stencil and hence it has been discovereda pressure reduction means, preferably in for form of a narrow elongateslot, is required.

[0010] Also according to a further development of this aspect of thepresent invention there is provided an applicator device for applyingviscous or paste-like fluid material to a surface therebeneath andcomprising a main body having a through passage with an upper fluidinlet and having a fluid outlet aperture in its lower region andincluding a sealing gasket or foil for sealing said outlet apertureagainst the surface therebeneath and said gasket or foil being formedfrom a sheet of flexible material with an uninterrupted or continuous,non-apertured outer part extending around the periphery of said outletand surrounding an inner aperture or apertured inner region of saidgasket or foil; characterised by the feature that the main body is aplate-like member which is adapted to the shape of the bottom of anelongate paste or other viscous material containing reservoir so as tobe sealable thereagainst and having means for securing such to thereservoir, and that said upper fluid inlet is an elongate openingextending along a major portion of the length of the housing.

[0011] In a still further development of the present invention, the mainbody and viscous-material containing reservoir and outlet sealing meansare formed as a unit or integrally and comprise an elongate horizontallyextending, viscous material reservoir open at its top and having anelongate, horizontally extending, vertically or substantially verticallydisplaceable piston sealingly slidable in the reservoir, and anelongate, horizontally extending opening or other opening or openings inthe bottom of the reservoir forming outlet means and pressure reductionmeans for the viscous material as it is urged donwardly by the piston,and in which the peripheral side of said opening or openings is offlexible material and extends downwardly and forms a sealing surface offlexible material which surface extends as an uninterrupted orcontinuous, non-apertured outer portion extending around the peripheryof said outlet opening or openings and sealingly engageable or abuttablewith the surface of a stencil therebeneath, and spacing means extendingdownwardly from the bottom of said reservoir and outwardly of saidsealing surface on at least two opposite sides to limit the amount thesealing surface is flexed upwards when pressed against a stencil surfacetherebeneath.

[0012] Also according to the present invention there is provided, incombination, a solder paste screen printing machine including firstreciprocating means for effecting reciprocating displacements in ahorizontal direction and carrying a second reciprocating means foreffecting vertical or upward/downward reciprocating movement of onepressure member, or for effecting vertical or upward/downward movements,alternately, of two pressure members, and a paste applicator deviceincluding a solder paste reservoir with paste displacing member abovethe paste displaceable under the action of such pressure member ormembers for displacing paste downwardly through paste pressure reductionmeans forming part of the device to an outlet sealingly slidable, inuse, over a supporting printing stencil, wherein said pressure member orsaid pressure members provide the downward pressure via the intermediaryof said paste to effect sealing of the applicator device against thestencil and act on the applicator device to effects said horizontaldisplacements thereof.

[0013] In leading to a further development, it has been found that withcertain solder paste screen printing machines using the above-mentionedapplicator device or other applicator devices, and especially with moresophisticated machines having pressure feed-back loop systems or closedloop feed-back systems, the pressing member or members are normally notable to effect the necessary range of downward displacement to move thepiston for the sufficient amount since such machines are initiallyset-up for only a limited amount of vertical displacement and when suchamount is exceeded (which normally indicated the wearing of a hitherto,known squeegee blade), the printing machine cuts off and ceases tooperate. Whilst this cut-off feature can be overridden and the machinereactivated, the process, it can prove troublesome and it is an objectof a further aspect of the present invention to provide an adaptordevice which will enable applicator devices and/or elongate reservoirsfor solder paste including a displaceable elongate piston to be readilydisplaced by the pressing members of a large range of solder pastescreen printing machines.

[0014] The further aspect of the present invention provides a simpleform of adaptor that is purely mechanical and does not require any powersource (such as pneumatic, hydraulic or electric) other than thedownward force exerted by the pressing member or members of a solderpaste or other viscous fluid printing machine which may have hithertocarried the known squeegee blades for solder paste. Also in some cases,the back pressure exerted on the printing machine can cause damage tothe machine.

[0015] According to a broad second aspect of the present invention thereis provided an adaptor device for enabling a solder paste or otherviscous fluid material applicator device, which is for receiving orincludes an elongate solder paste or other material reservoir containingan elongate piston displaceable therein for displacing the solder pasteor other material, to be acted upon by the one or more verticallydisplaceable pressing members of a solder paste or other material screenprinting machine, comprising a preferably elongate piston pressingmember locatable on the piston of the elongate reservoir and connectedvia at least one one-way movement enabling device to a preferablyelongate pressure receiving member which is to be acted upon by thepressing members of a screen printing machine in a downward direction,with said one-way movement enabling device only normally permittingmovement of said pressure receiving member in an upward direction awayfrom said piston pressing member and wherein with every downwarddisplacement of the piston pressing member and receiving member, solderpaste contained within the reservoir is urged downwardly and out of saidreservoir, said pressure receiving member being biased away from saidpressing member so as to be displaced upwardly to its original positionfollowing each downward displacement thereof.

[0016] The surface of said pressure receiving member which is engaged bysaid pressing member of the printing machine is preferably of or at aheight or displaced to a height such that in operation the downwarddisplacement of the pressing members of the screen printing machine doesnot exceed that as may be permitted by the machine for normal operationwithout stopping of the machine. Thus, it is important the maximumdownward displacement of the pressing member and the pressure receivingmember during each downward stroke of the machine will not exceed thatpermissible for the normal range of movement of the pressing members ofthe printing machine which is normally its amount of expected flexing ofknown squeegees e.g. about up to 3 mm likely 0.5 mm, i.e. within normaltolerances. For the first downward displacement of the pressurereceiving paste or other fluid, the applicator and adaptor device aresuch that the back pressure in the paste will act to safely limit thedownward movement of the machine. The return of the pressure receivingmember to its original height and the operation of the one-way movementenabling device will ensure the maximum downward movement of the machineis not exceeded.

[0017] The maximum spacing between the piston pressing member and thepressure receiving member is preferably achieved by two spaced apartprojections extending from the pressing member and each through anaperture thereabove in the pressure-receiving member to also act as aguide means and has an enlargement (such as the head of a threadedmember or projecting captive metal balls of a quick release device)which limits the amount said two members may be biased apart. The twomembers may be optionally separated when changing reservoirs (bydetaching the threaded members or retracting the balls of thequick-release device).

[0018] Preferably the one-way movement enabling means is a ball-lock(preferably with a annular taper of 5° per side i.e. a 10° includedangle) and has the advantage over one-way step-wise or graduated ratchetdevices of enabling movement in one direction of any desired amount.Each ball lock is preferably releasable by screwing down or pressingdown a ball displacement cap which displaces the balls downwardly todisengage the balls from the taper and enable movement in twodirections.

[0019] The pressure receiving means of the adaptor device will normallyrest on top of the paste reservoir or be biased to a position thereaboveand the pressing member acts on the piston of the paste reservoir and isdisplaced downwardly by force being transmitted from the pressing memberof the paste printing machine onto the pressure receiving member (thedevice sometimes referred to later herein as the “incremental cap”) andthen the one-way movement enabling device, to the piston pressingmember.

[0020] The piston pressing member is preferably elongate and coextensivewith the piston of the reservoir and the connection between the twomembers guides the piston pressing member such that any tendency for thepiston to tilt (erratically about its horizontal traverse axis) isminimised or reduced.

[0021] In a broad second aspect of the present invention there isprovided an adaptor device for enabling a paste or other viscousmaterial applicator device for receiving or including an elongate solderpaste reservoir containing an elongate piston displaceable therein fordisplacing the solder paste to be acted upon by the verticallydisplaceable pressing members of a solder paste screen printing machine,and said adaptor device comprises a pressure receiving member locatableon the elongate reservoir and/or the piston of the applicator device andto be acted upon by the pressing members of a screen printing machine ina downward direction, and piston displacing means which moves downwardlywith said pressure receiving member and which cause the piston to bedisplaced downwardly when said pressure receiving member is acted on bysaid pressing members to urge solder paste contained within thereservoir downwardly; the surfaces of said adaptor device which areengaged by said pressing members of the printing machine being of or ata height or displaceable within a limited range such that, in operation,the downward displacement of the pressing members of the screen printingmachine does not exceed that as may be permitted by the machine fornormal operation without stopping of the machine. The downwarddisplacement is limited by the back pressure of the viscous material asonly a small amount of the viscous material is dispensed during eachpass of the applicator device on the machine.

[0022] The invention will be described further, by way of example, withreference to the accompanying drawings, in which:

[0023]FIG. 1 is a schematic cross section through a first embodiment ofthe invention;

[0024]FIG. 2 is an exploded view from above of the separated componentparts of an embodiment of the invention as a practical realisation ofthe schematic embodiment of FIG. 1 including the top of the main bodyplate and parts thereabove of the applicator device of FIGS. 2 and 5.

[0025]FIG. 3 is a perspective view of the device of FIG. 2 from aboveand one side and with one of the pusher plates being removed to show thecastellated bottom pressure distribution plate of the remaining one;

[0026]FIG. 4 is a view similar to FIG. 3 wherein the upper,reservoir-clamping and reinforcing member has been removed;

[0027]FIG. 5 is a perspective view from below of the upper pusher plateswherein the castellated pressure distribution plates (normally at thebottom) are shown juxtaposed prior to interdigitation;

[0028]FIG. 6 is an inverted plan of the pusher plates of FIG. 5 andinterdigitated pressure distribution plates;

[0029]FIG. 7 is a line drawing plan from above of the main body of FIG.2 showing the groove for a sealing 0-ring for sealing with the reservoirand the central pressure reduction slot;

[0030]FIG. 8 is a plan view from below of the main body of the device ofFIGS. 2 and 7;

[0031]FIG. 9 is a perspective view from below showing the bottom of themain body of the applicator device (without the components attached tothe upper side of the main body and comprising the reservoir, clampinghousing and pusher plates) and showing the outer lateral spacing memberswith the continuous sealing foil therebetween and overlying thecontinuous O-ring with the central pressure reduction slot and endblanking members.

[0032]FIG. 10 is an exploded perspective view of the separatedcomponents of the parts of FIG. 9 comprising the bottom of the main bodyplate and the parts connected thereto;

[0033]FIG. 11 is a schematic sectional view through an alternativeembodiment of the invention wherein the pressure reduction means and thecontinuous sealing foil means are integrally formed in the bottom of thepaste reservoir cartridge as are the lateral spacing shoes;

[0034]FIG. 12 is a perspective view from above and one end of a workingversion of the an embodiment of the adaptor device according to thesecond aspect of the invention and showing two pressing bars, oneseparated and on its side, connectable to the alternate upward/downwardmovement devices of the machine;

[0035]FIG. 13 is a perspective view from above and one end of the deviceof FIG. 12 i.e. a solder paste reservoir in an applicator device with anespecially hook-like mounting arrangement with securing levers centrallyfor enabling mounting on a specific paste printing machine;

[0036]FIG. 14 is a schematic sectional illustration on line X-X of theadaptor devices of FIGS. 12 and 13 (without mounting devices) showingthe elongate extension of the piston pressing member and pressurereceiving member and the spacing of the two one-way movement enablingdevices in their starting positions (as FIG. 16) prior to any steppingof the piston pressing member away from the pressure receiving member;

[0037]FIG. 15 is an enlarged schematic end section on line Y-Y throughan adaptor device and one of the two one-way movement enabling devicesaccording to one embodiment of the invention and located on anapplicator device and an elongate solder paste reservoir; and

[0038] FIGS. 16 to 18 are schematic illustrations of the variousoperational conditions of an adaptor device similar to that of FIGS. 14and 15.

[0039] In FIG. 1 a solder paste applicator device 1 is illustrated andincludes a main body or base plate 2 having an upper side 3 withcontinuous groove 5 in which a sealing O-ring 4 is located in and onwhich the upper side 3 an elongate, horizontally extending solder pastereservoir 6 in the form of a replaceable cartridge is located and thebottom flanges 6A having abutting against upstanding shoulders and beingclamped in position by a surrounding channel-like clamping member 12 (inFIG. 2) (but not shown in FIG. 1) screwed to base plate 2. The pastereservoir 6 of plastics material has sealingly slideable therein agenerally horizontally extending elongate piston 7 (only shown inFIG. 1) also of plastics material which rests on the upper surface ofsolder paste 8 and one or a plurality of outlet apertures (not shown)are provided in the bottom 9 of reservoir 6 and through which paste maybe discharged therefrom under the action of pressure on piston 7—saidpressure being alternately applied by two generally L-sectioned driversor pusher plates 10, 11 which act as pressure transmission means from ascreen-printing machine (not shown). The pusher plates 10, 11 are eachmountable in place of known squeegee blades (with reference to FIG. 20of GB 2341347) which have been hitherto mounted with the yokes of aknown vertical reciprocating mechanism (not shown) and carried by areciprocably displaceable carriage of a solder paste screen printingmachine. (With reference to FIG. 20 of GB 2341347, the present pusherplates 10, 11 take the place of known adapter blades 83, 84 and would bemountable on yokes 78, 79 of the vertical reciprocating mechanism 79carried by carriage 74 of a screen printing machine.)

[0040] In FIGS. 2-10 the same or similar reference numerals are used asin FIG. 1 i.e. for similar parts, although a clamping member 12 isillustrated in the form of an inverted U-shaped channel member 12 (FIGS.2 and 3) which has a central aperture shaped to closely surround theouter sides of the paste reservoir 6 so as to provide lateral supportagainst outward bulging of the walls of the reservoir because of thepressure of the paste and also to clamp the reservoir 6 against the mainbody or base plate 2 by means of two threaded members 13 extendingthrough apertures therein and engageable in threaded bores 13A (only oneshown) in body 2 on spacer thereon.

[0041] In FIGS. 3 and 4 one of the pusher plates 11 has been omitted soas to reveal the remaining one 10 which comprises an upper part 10Awhich is securable to the carrier member (not shown) of thereciprocating mechanism of the solder paste screen printing apparatusand extends downwardly to fit into one part of the paste reservoir 6 andhas at the bottom thereof a pressure distribution plate 14 secured byscrews and having a plurality of horizontally extending rectangularflanges 14A or castellations which extend partway across the body of theelongate paste reservoir cartridge 6 and interdigitate with similarlybut offset projecting flanges 15A of distribution plate 15 of theopposite pusher plate 11—see FIGS. 5 and 6 in this connection whereinthe pusher plates have been inverted to illustrate the interdigitationof the projecting flanges 14′, 15′ of the pressure distribution means14. The ends 14B, 15B of each of the distribution plates 14, 15 arerounded to conform with the shaping of the interior walls of thecartridge.

[0042] The bottom of the inverted channel section 12 which clamps thereservoir in position extends through a number of spacer plates and ontothe main body 2.

[0043] In FIGS. 2-8 the upper components of the device 1 are illustratedcomprising the main body 2 having the continuous groove 5 with acircular cross-section O-shaped sealing ring 4 located therein to extendthereabove and to be in sealing abutting relationship with the bottom 6Aof the paste reservoir 6 and the outlets therein. Main body 2 has arecessed inlet portion 2A surrounded by the groove 5 for receiving pastefrom reservoir 6 and has a narrow central slot 18 extending axiallytherealong which forms a pressure reduction means for paste urged out ofthe reservoir 6 and leads to the outlet portion 2B in the underside ofthe main body 2 and into the space defined peripherally by the lowersealing foil 19. Shoulder portions 20 are provided in the top of themain body 2 and against which the flanges 6B at the bottom of the paste6 reservoir fit so as to be located there and the inverted U-shapedsection clamping member 12 is located thereover and secured by threadedsecuring means 13 passing through holes therein and into threadedapertures 21 in the opposite ends of the main body 2.

[0044] The central paste reservoir encircling aperture 22 of theclamping member 12 has plurality of notches 22A around its edge whichaccommodate reinforcing ribs 6C in the outer sidewalls of the pastereservoir 6 and the clamping device 12 can securely clamp the bottomflanges 6A, 6B of the reservoir against the bottom body plate 2.Additional reinforcing means (not shown) to prevent outward bulging ofthe main walls of the reservoir 6 may be provided. The paste displacingpiston 7 lies within the paste reservoir 6 and is of similarcorresponding shape to the inner walls thereof and extends therealong.

[0045]FIGS. 7 and 8 are a plan and underneath plan of the main body 2.

[0046]FIG. 9 is an underneath perspective view of the main body plate 2and components attached thereto. The lower side of main body plate 2 haselongate side faces 2C (for receiving spacing plates or shoes 26) andthen, inwardly, two step or shoulder portions 2D and a bottom surface 2Eis provided for O-ring 16 and inwardly thereof the apertured outletportion 23 is provided. FIG. 10 shows the components of FIG. 9 separatedand these might be described with reference to the assembly/locationstages relative to the bottom of the main body plate 2 as follows. Firstthe lower resilient rubber sealing O-ring 16 is located in the groove 17and projects thereabove or therebelow in use. Then a foil retainingplate 24 is located by suitable means on the main body plate 2 and hasinclined lateral lips or edges 24A facing each other on either side ofthe inner aperture 25 and which are to retain the continuous sealingfoil 19 as will be described subsequently. (It is envisaged that priorto location of the foil retaining plate 24, an additional continuousresilient member (not shown) may be clamped thereunder with edgesabutting lower than the crown (normally above the crown) of the O-ringin use so as to prevent solder paste accumulating laterally outwardly ofthe O-ring) Subsequently the two spacer plates 26 or “shoes” are locatedwith screws laterally either side of the central elongate aperture 2Bwith the pressure reduction slot 18 in the middle and the combinationscrewed together to the bottom of the main plate 2 to hold such inposition. Then the continuous resilient sealing gasket or foil 19(similar to that as described in GB 2341347A) is flexed and inserted andlocated so as to be retained by the side edges 24A of the foil retainingplate 24 and abutting against the resilient O-ring 4 to form a good sealtherewith when pressed against a stencil (not shown) locatedtherebeneath. End stops or blanks 27 are of resilient material may belocated either end of slot 18 and held to restrict an outward flow ofpaste of the ends and may be of adjustable or of variable length ordifferent length to accommodate for different widths of aperturearrangements in the stencil (not shown) to be used for a printingoperation.

[0047] In use with the paste reservoir 6 containing solder paste 8 andthe piston 7 being upwardly disposed within the inside of the reservoiron top of the paste 8 and the pusher plates 10 and 11 screwed to thevertical reciprocating bars (not shown) of the reciprocating mechanismof the screen printing machine (not shown), and with the reservoir 6 andattached bottom plate 2 and components therebeneath such that at thecommencement of one operating cycle of the printing machine, one pusherplate 10 is raised and the other 11 is lowered to press against thepiston 7 and urge paste out of the reservoir 6 through the one orplurality of bottom apertures 9 in the bottom and through the pressurereduction slot 18 into the space defined between the inner surfaces ofthe sealing O-ring 4 and edges of the resilient gasket or foil 19 whichhas been flexed. The foil 19 has been flexed upwardly by being pressedagainst the upper surface of the stencil (not shown) therebeneath andwhich is to have the solder paste pressed therethrough to be printed.The pressure on the device 1 is exerted by the vertical reciprocatingmechanism (not shown) of the screen printing machine via the pusherplates 10 and 11 and this not only pressurises the paste 8 but also viathe paste acting on the reservoir bottom and/or the bottom plate 2,presses the lower parts of the applicator device 1 against the stenciland into peripheral sealing engagement with it via the sealing foil 19.The spacer shoes 26 on either side limit the upward deflection of thefoil 19 and may be of a material such as PTFE or other preferablyslidable material (and may even be a plate surrounding a slot therein).

[0048] The stenciling operation is then effected by the printing machinemoving horizontally and carrying with it the applicator device 1 to theend position whereupon for the next stroke the pusher plate 11 is raisedand the pusher plate 10 lowered to act against the piston 7 and ahorizontal displacement then takes place in the opposite direction in asimilar manner with plate 10 pressing the device 1 against the stencilto form a seal with the gasket or foil 19 thereagainst and also causingthe horizontal movement again by horizontal pressure against the wallsof the reservoir 6.

[0049] It is to be appreciated that unlike hithereto known deviceshaving motive power means or devices separate of the machine fordisplacing the paste, the pressure in the present invention is appliedvia the pusher plates 10 and 11 and not only exerts pressure on thepiston 8 so as to drive the solder paste out of the reservoir 6, but theapplicator device 1 is constructed and arranged such that this downwardpressure is also transmitted via the paste 8 through the components ofthe body 1 and to the shoes 26 and causes the necessary pressure forsealing of the foil 19 against the stencil surface and, furthermore, byacting against the side walls of the reservoir 6, also effects thedisplacement in horizontal directions of the applicator device over thestencil. Thus no separate pressurisation device for the paste 8 isnecessary other than the mechanical forces from the reciprocatingmechanism of the printing machine. As a consequence of this two-foldpressure application, greater pressure is exerted on the paste than isactually necessary to displace such out of the reservoir and through theapertures in the stencil therebeneath and is of such magnitude as wouldotherwise create problems in printing in that the paste would be forcedinto undesirable regions and leak. It has been found necessary toprovide the pressure reduction means for the paste 8 which in theexample shown is in the form of a narrow slot 18 formed within the mainbody plate 2 although such may be provided as a separate componentseatable in a larger slot on shoulders thereof and thus would enable thepressure reduction to be varied dependent upon the paste condition etc.

[0050] It is also envisaged that the condition of the paste within thereservoir 6 might be improved as a result of a tilting or rocking motionof the piston 4 about an axis generally transverse to its longitudinaldirection of extension and this may be created by the construction oroperation of the pressure plates 10 and 11 For example, they might haveoppositely, inclined or curved surfaces or a “crown” or a camarrangement or other device to create this additional alternating ortilting action in opposite directions for each stroke which will betransverse to the normal horizontal direction of a movement during aprinting operation.

[0051] Whilst not shown, the paste cartridge 6 might normally have aplurality of very large paste outlet apertures or a single elongate slotin the bottom which are/is not such as to cause any significantreduction in the pressure thereof and such normally have on the lowersurface, a removable foil which is removable prior to use to enable thepaste to flow out thereof. It is also envisaged as a possibly preferredmodification of this embodiment for the paste reservoir to be providedintegrally formed or otherwise on the maid body plate 2 as an upstandingcontinuous wall surround the slot 18 and providing interrupted flowthereto. In this arrangement, the main body plate with reservoir wouldbe returned for recharging.

[0052] In FIG. 11 an alternative embodiment is illustrated comprising anintegrally formed or mainly integrally formed plastics materialapplicator device 28 having similar pusher plates 10 and 11 asattachments which are simply provided to adapt an existing screenprinting machine in place of the squeegee blades thereof so as to enablethe vertical and horizontal reciprocating mechanism to act upon thepaste cartridge piston 29 and side walls 30 of the reservoir 31 forsolder paste 32 to effect the necessary displacement. In the embodimentof FIG. 11, which is illustrated schematically, it is envisaged thatmain components of the applicator device be integrally formed in thatthe paste reservoir 31 has an elongate slot 33 in its bottom 13, 14acting as a pressure reduction means for the paste 32 being expelledtherefrom and the side walls 35 defining the pressure reduction slot orportions extend therebeneath and are resilient so as to define acontinuous surface 36 surrounding the lowermost aperture 39 in thebottom wall 34 so as to provide a sealing surface 36 against a stencilwhen located therebeneath and when pressed thereagainst and will have adegree of resilience to enable such seal to be effected. Laterally oneither side of the resilient surfaces 36 forming the seal, there is arecess 38 and then shoulders or downwardly extending spacing projections39 which are equivalent to the spacing “shoes” 26 of FIG. 10 and whichwill slide on the surface of the stencil. There are also extensionsextending in opposite direction on either side to provide stability forthe sliding movement and will limit the upward deflection of theresilient surfaces 36 when the device 28 is pressed against the stencilsurface. Otherwise, the piston 29 and members 10, 11 etc. will besimilar to that already described and be downwardly displaceable topress paste out of the reservoir cartridge. This arrangement hasparticular advantages in that the whole unit may be disposable afteruse. It is of course envisaged that the applicator device 28 namely thecartridge reservoir, will be integrally formed as plastics or othersimilar material.

[0053] It will be appreciated the downward pressure which causes sealingof the applicator devices according to the present invention is via thepaste which being incompressible paste transmits such downwardly mainlyagainst the walls defining the pressure reduction means etc., to createthe peripheral seal via foil 19 at the outlet.

[0054] An adaptor device 41(or “incremental cap”) is illustrated inFIGS. 12-15 the drawings and is schematically illustrated in FIG. 13 onan elongate replaceable paste reservoir 2 mounted on a paste applicatordevice 43 and comprises an elongate pressing member 44 which is to reston and downwardly displace the elongate piston (7 in FIG. 1) of thereservoir 2 to displace paste therefrom out of the bottom and throughthe applicator device 43 whose bottom outlet is peripherally sealedagainst a stencil therebelow (not shown) as the device 43 slides overthe stencil.

[0055] The piston pressing member 44 is connected via two, one-waymovement enabling devices or ball locks 46 to an elongate pressurereceiving member 47 such that the member 44 is displaceablesubstantially parallely with member 47 and member 47 is biased to beable to move in said one-way away from the piston pressing member 44.

[0056] As shown in FIG. 15 each ball lock 46 comprises a tubular member48 connected by a threaded screw with knurled head 45 to piston pressingmember 44. The tubular member 48 slidingly extends through an aperturein pressure receiving member 47 and has an outwardly extending upperflange 48A to prevent downward removal. The tubular member 48 is closedor restricted at its lower end and contains a compression spring 49which extends out of member 48 into contact with a plastics screw cap 50which in turn has external threads 50A engaging with an internallythreaded passage portion 51A of an aluminium annular cap 51 which isconnected at its lower region to an annular hardened steel taper lock 52with part conical surfaces 52A converging upwardly and against whichball bearings 53 of the lock may jam. The balls 53 are supported on anannular ring 54 which slides on the outside of the tubular member 48 andis biased upwardly by spring 55 into locking engagement with surfaces52A and upwardly with the outer surface of tubular member 48. The lowerend of spring 55 rests on pressure receiving member 47. The lower end ofscrew cap 50 is engageable with the circle of balls 13 by being screweddown (or pushed down and twisted to hold down when a bayonet typefilling is removed) and can disengage such balls from the surface 52Aetc., so as to release the one way device 46 and enable movement in twodirections. Otherwise the one way device 46 normally only enablesmovement of tubular member 48 and cap 46 and pressure receiving member47 upwardly away from member 44 to a limited extent determined by stops58 on the end of guide posts 58A which move through apertures 58B inmember 47. Downward movement of the whole adaptor device 46 to displacethe reservoir piston 7 is under the alternate action of pressing members56 when attached to a solder paste screen printing machine (not shown).In downward movement, there is no relative movement between members 44and 47 as the device 6 will be locked.

[0057] The device of FIG. 12 is for a common printing machine withalternately mechanically reciprocating squeegee blade holders and twoconnector bars 56, 56A, one shown with scalloped ends to abut eitherside of the lower parts of one-way devices 16.

[0058] In FIGS. 13 the hook shaped device 57 is simply an attachmentdevice for a printing machine having only a single verticallyreciprocating device and is of little importance to the inventiveconcept.

[0059] There will now be described preferred practical/operationalfeatures of the adaptor device:

[0060] The device 41 is fitted to paste printing machines (not shown)(via 56, 56A or 57) that features a squeegee down force feedback system.The concept is to provide a constant working height (e.g. 41.5 mm) soavoiding excessive vertical squeegee pressing member travel during theprint stroke. The device 41 is purely mechanical with no outside powersource of any kind required except the downward and horizontalmechanical pressures of the printing machine. The drive to dispense thepaste is supplied by the squeegee pressing member down force applied tothe member 47. The member 47 features two one-way movement enablingmechanisms 6. Each successive downward movement of the machine squeegeemechanism extends follower plate or member 44 onto the piston thusdriving the paste. The pressure receiving member 47 is biased back toits original level (determined by stops 58) after each print stroke bysprings 49, leaving the follower plate 44 in contact with the piston 7.The whole process is then repeated until the paste cartridge 6 isemptied.

[0061] Paste replenishment requires that the paste applicator device 43be removed from the machine. In the case of a permanent fixture to amachine, a quick release mechanism is incorporated to allow applicator43 to be removed from the machine interface. In order to replace orrecharge the paste cartridge or reservoir 6, the one-way mechanisms 46must be disabled. Turning the caps 50 on the tops of the mechanisms 46,one turn in a clockwise direction releases each and allows the followeror piston pressing member 44 to be returned to be adjacent member 47. Anew cartridge 6 can be loaded into the applicator device 43 or theexisting cartridge 6 recharged. Once reassembled, the one-way mechanisms46 have to be re-enabled. This is done by simply turning the caps 50 oneturn in a counter clockwise direction to enable ring 54 to act on balls53 to activate the one-way movement enabling devices 46 to enablefurther printing.

[0062] The upward movement of the pressure receiving member 47 islimited by two stops 58 which each comprise a large headed screw memberhaving a shank 58A as guide post extending through an aperture 58A onmember 47 and screwed onto pressing member 44 and being such as to limitthe maximum spacing between members 44 and 47 although normally theback-pressure of the paste ensures that the maximum downwarddisplacement permissible for the pressing members of the reciprocatingsqueegee mechanism of the printing machine as mentioned previously isnot exceeded. This is sometimes merely the amount by which a hithertoused squeegee would flex under pressure. Thus adaptor device of theinvention will operate so as to prevent the printing machineunnecessarily cutting off.

[0063] The member 44 preferably moves parallel to member 47.

[0064] In FIG. 16 the applicator device 46 is in its starting positionand when pressure is exerted downwardly on member 47, the whole devicemoves down until stopped by back pressure in the paste. In FIG. 7, onrelease of the down pressure member 47 and 50-57 the one biased upwardlyaway from member 44 and the process then continues until an end positionsuch as in FIG. 18 is reached.

[0065] In an improvement to the adaptor device so that an operator, inuse, can be appraised of how much fluid material, normally solder paste,remains in the reservoir of the applicator device, at least one andpreferably two upstanding projections or pillars are mounted on thepiston pressing member of the adaptor device and each extends upwardlyand preferably passes through apertures in the pressure receiving memberand thus its relative extension above the aperture is representative ofthe paste remaining. Preferably a transducer and transmitting device orother position sensing and display or relaying means is provided todetermine the amount of projection of the projection or pillar throughthe aperture and above the pressure receiving member and to transmitsuch, preferably via radio or other wire less connection, to a receiverwhich displays the amount of paste remaining.

1. An applicator device for abutment by or attachment to the horizontaland the vertical mechanical displacement/reciprocating means hithertofor the squeegee blades of a solder paste printing machine for otherviscous fluid material printing machine, said applicator device beingfor applying paste-like or other viscous fluid material to a surfacetherebeneath and comprising a body having a through passage with anupper, fluid inlet extending along the body and having a lower, fluidoutlet aperture in its lower region extending along the body with apressure reduction means between the inlet and outlet for reducing thefluid material pressure, a sealing gasket or foil for peripherallysealing said outlet against a stencil by being pressed against thestencil surface therebeneath with said gasket or foil being formed froma sheet of flexible material with a uninterrupted or continuous,non-apertured outer part extending around the periphery of said outletand surrounding an inner aperture or apertured inner region of saidgasket or foil, and an elongate, horizontally extending reservoir forfluid material formed with or detachably mounted on the upper side ofsaid main body and extending to be in communication with said inlet ofthe main body or having a fluid outlet or outlets at and along its lowerside in communication with said inlet of the main body, and adisplaceable piston extending in said reservoir for displacing fluid outof said reservoir or outlet or outlets of the reservoir and into thefluid inlet on the main body and then via the pressure reduction meansto the outlet defined by said sealing gasket or foil; said piston beingaccessible or actuable from above by one or more mechanical pressingmembers connectable to or abuttable to said mechanicaldisplacement/reciprocating means of the printing machine for thepreviously removed squeegee blades so as to be displaceable thereby andsaid applicator device being without and not requiring any otherseparate motive power source for such displacement or not requiring anypipe ducting means for any such displacement motive power source (e.g.without any dedicated pneumatic or hydraulic displacement means) otherthan to receive mechanically transmitted displacement forces from saidmechanical displacement/reciprocating means of the printing machine. 2.A device as claimed in claim 1, in which two pusher members are providedeach connectable to the horizontal and vertical reciprocating mechanismof a solder paste printing machine so as to be alternatelyupwardly/downwardly operatively displaceable at the end of eachhorizontal displacement, said pusher members comprising two elongatepusher plates or blades which alternately act on the displaceable pistonof the elongate paste reservoir.
 3. A device as claimed in claim 2, inwhich the plates or blades each act via a pressure distribution plate orportion thereof which spreads the pressure across the piston transverseto its direction of extension to minimize any backwards/forwards tiltingmovement of the piston.
 4. A device as claimed in claim 3, in which endpressure plate or blade has a generally horizontally extending lowerpressure distribution portion of a shape so as to interdigitate with asimilarly shaped oppositely arranged, lower portion of the other plateor blade.
 5. A device as claimed in claim 4, in which the pressuredistribution portions of the plates or blades are of an interdigitatablecastellated outline.
 6. A device as claimed in any of claims 2 to 5, inwhich the pusher plates or blades are adapted (for example by beingcurved or cam mounted or otherwise rocking) to cause an alternatetilting displacement of the piston along its length (i.e. from side toside), in addition to pressing down with such sideways rocking ortilting provided to improve/maintain the characteristics of the solderpaste.
 7. A device as claimed in any of claims 1 to 6, in which saidmain body is an elongate plate-like member having an elongate slotprovided therein as said pressure restriction means between either sidethereof.
 8. A device as claimed in claim 7, in which the reservoir issecurably mountable on the upper side of said plate with said pasteoutlet in communication with said slot.
 9. A device as claimed in claim7, in which the reservoir is provided by continuous upstanding wall onsaid plate-like member extending around said elongate slot to containsolder paste.
 10. A device as claimed in any of claims 1 to 9, in whicha sliding or slideable spacing member or members with lower planarface(s) is connected to the bottom of said main body and extends alongopposite sides of the sealing gasket foil which foil when hanging freelyand not having the counter-pressure of a stencil, has a sealing edgewhich extends beneath the lower planar face of the spacing member andsaid spacing member will be a factor in determining the amount thesealing edge is displaced upwardly against resilient means when thesealing edge and spacing member are supported on a stencil.
 11. A deviceas claimed in any of claims 1 to 10, in which a continuous resilientring is located between the main body and the sealing gasket or foilextending around the lower fluid outlet to form a seal with said foil inuse.
 12. A solder paste stencil printing machine including areciprocating mechanism in combination with an applicator device asclaimed in any of claims 1 to 11, constructed such that wherein in use,the force exerted by the pressing members or pusher plates to exert apressure and driving force not only horizontally reciprocates theapplicator device and reservoir over the surface of the stencil but alsoexerts a downward pressure on the displaceable piston and solder pastethereunder so as to provide the pressure to maintain the gasket or foilin sealing contact with the stencil therebeneath and cause the solderpaste to be discharged from the reservoir and through the apertures inthe stencil onto a circuit board or other electronic component orsubstrate therebeneath.
 13. A applicator device for applying viscous orpaste-like fluid material to a surface therebeneath and comprising amain body having a through passage with an upper fluid inlet and havinga fluid outlet aperture in its lower region and including a sealinggasket or foil for sealing said outlet aperture against the surfacetherebeneath and said gasket or foil being formed from a sheet offlexible material with an uninterrupted or continuous, non-aperturedouter part extending around the periphery of said outlet and surroundingan inner aperture or apertured inner region of said gasket or foil;characterised by the feature that the main body is a plate-like memberwhich is adapted to the shape of the bottom of an elongate paste orother viscous material containing reservoir so as to be sealablethereagainst and having means for securing such to the reservoir, andthat said upper fluid inlet is an elongate opening extending along amajor portion of the length of the housing.
 14. An applicator device forapplying viscous or paste-like fluid material to a surface therebeneathincluding a main body and viscous-material containing reservoir andoutlet sealing means which are formed as a unit or integrally formed andcomprise an elongate horizontally extending, viscous material reservoiropen at its top and having an elongate, horizontally extending,vertically or substantially vertically displaceable piston sealinglyslideable in the reservoir, and an elongate, horizontally extendingopening or other opening or openings in the bottom of the reservoirforming outlet means and pressure reduction means for the viscousmaterial as it is urged downwardly by the piston, and in which theperipheral side of said opening or openings is of flexible material andextends downwardly and forms a sealing surface of flexible materialwhich surface extends as an uninterrupted or continuous, non-aperturedouter portion extending around the periphery of said outlet opening oropenings and sealingly engageable or abuttable with the surface of astencil therebeneath, and sliding or slideable spacing means extendingdownwardly from the bottom of said reservoir and outwardly of saidsealing surface on at least two opposite sides to limit the amount thesealing surface is flexed upwards when pressed against a stencil surfacetherebeneath.
 15. In combination, a solder paste screen printing machineincluding first reciprocating means for effecting reciprocating squeegeedisplacements in a horizontal or substantially horizontal direction andcarrying a second reciprocating means for effecting vertical or otherupward/downward reciprocating movement of one pressure member, or foreffecting vertical or upward/downward movements, alternately, of twopressure members, and a paste applicator device including a solder pastereservoir with paste displacing member or piston above the pastedisplaceable under the action of such pressure member or members fordisplacing paste downwardly through paste pressure reduction meansforming part of the device to an outlet sealingly slideable, in use,over a supporting printing stencil, wherein said pressure member or saidpressure members provide the downward pressure via the intermediary ofsaid paste acting on the device to effect sealing of the applicatordevice against the stencil and act on the applicator device to effectsaid horizontal displacements thereof.
 16. An applicator device asclaimed in any of claims 1 to 15, in combination with an adaptor devicefor enabling said applicator device to be acted upon by the one or morevertically or substantially vertically displaceable pressing members ofa solder paste screen printing machine, comprising a piston pressingmember locatable on the piston of the elongate reservoir and connectedvia a one-way movement enabling device to a pressure-receiving memberwhich is to be acted upon by the pressing members of the screen printingmachine or an intermediary pressing plate/member connected to saidpressing member in a downward direction with said one-way movementenabling device only normally permitting movement of saidpressure-receiving member in an upward direction away from said pressingmember and wherein with every downward displacement of the pressingmember and receiving member, solder paste contained within the reservoiris urged downwardly and out of said reservoir, said pressure receivingmember being biased away from said pressing member so as to be displacedupwardly to its original position following each downward displacementthereof.
 17. A combination as claimed in claim 16, wherein incombination with a solder paste screen printing machine in which thesurface of said pressure receiving member which is engaged by saidpressing member of the printing machine is of or displaced to a heightsuch that in operation the downward displacement of the pressing membersof the screen printing machine does not exceed that maximum displacementof the machine pressing member as permitted by the machine for normaloperation without stopping of the machine.
 18. A combination as claimedin claim 16 or 17, in which spacing between the pressing member and thepressure-receiving member is achieved by the provision of one or twospaced apart projections extending from the pressing member and eachthrough an aperture thereabove in the pressure-receiving member and hasan enlargement which limits the amount said two members may be biasedapart.
 19. A combination as claimed in claim 18, in which the twomembers are optionally separable when changing reservoirs (e.g. bydetaching the threaded members or retracting the balls of thequick-release device).
 20. A combination as claimed in any of claims 16to 19, in which the one-way movement enabling means is a ball-lockdevice having an annular taper which enables movement in one directionof any desired amount.
 21. A combination as claimed in claim 20, inwhich each ball-lock has a ball displacement cap and is releasable byscrewing down the ball displacement cap which displaces the ballsdownwardly to disengage the balls from the taper and enable movement intwo directions.
 22. A combination as claimed in any of claims 16 to 21,in which the pressing member is elongate and coextensive with the pistonof the reservoir and the connection between the two members guides thepressing member such that any tendency for the piston to tilt isminimized or reduced.
 23. An applicator device as claimed in any ofclaims 1 to 15, in combination with an adaptor device for enabling thepaste or other fluid material applicator device to be acted upon by thevertically displaceable pressing member or members of a solder paste orother viscous fluid material screen printing machine, said adaptordevice comprising a pressure receiving member locatable on the elongatereservoir and the piston thereof and to be acted upon by the pressingmembers of a screen printing machine in a downward direction, and pistondisplacing means which moves downwardly with said pressure receivingmember and which cause the piston to be displaced downwardly when saidpressure receiving member is acted on by said pressing members to urgesolder paste or other viscous fluid material contained within thereservoir downwardly; the surfaces of said device which are engaged bysaid pressing member or members being of or at a height or displaceablewithin a limited range such that, in operation, the downwarddisplacement of the pressing members of the screen printing machine doesnot exceed that as may be permitted by the control means of the machinefor normal operation without stopping of the machine.
 24. An applicatordevice substantially as herein described with reference to theaccompanying drawings.
 25. An adaptor device for enabling a solder pasteor other viscous fluid material applicator device, which is forreceiving or including or includes an elongate solder paste or othermaterial reservoir containing an elongate piston displaceable thereinfor displacing the solder paste or other material, to be acted upon bythe one or more vertically displaceable pressing members of a solderpaste or other viscous material screen printing machine, said adaptordevice (1) comprising a piston pressing member locatable on the pistonof the elongate reservoir and connected via at least one one-waymovement enabling device (6, 6) to a pressure-receiving member which isto be acted upon by the pressing members of a screen printing machine ina downward direction, with said one-way movement enabling device onlynormally permitting movement of said pressure-receiving member in anupward direction away from said piston pressing member and wherein withevery downward displacement of the piston pressing member and pressurereceiving member, solder paste or other material contained within thereservoir is urgeable downwardly and out of said reservoir, saidpressure receiving member being biased away from said piston pressingmember so as to be displaced upwardly to its original position followingeach downward displacement thereof.
 26. An adaptor device as claimed inclaim 25, in which the spacing between the pressing member and thepressure-receiving member is achieved by two spaced apart projectionsextending from the pressing member and each through an aperture in thepressure-receiving member thereabove and each having an enlargement orstop.
 27. A device as claimed in claim 26, in which the position of thestops are adjustable to enable adaptation to a particular printingmachine operation which limits the amount said two members may be biasedapart.
 28. A device as claimed in any of claims 25 to 27, in which thetwo members are optionally separable for changing reservoirs.
 29. Adevice as claimed in any of claims 25 to 28, in which the one-waymovement enabling means is a ball-lock including an annular taper andoperates on a one-way ratchet device for enabling movement in onedirection by any amount.
 30. A device as claimed in claim 29, in whicheach ball-lock is releasable by screwing or pushing down a balldisplacement cap which displaces the balls downwardly to disengage theballs from the taper and enable movement in two directions.
 31. Anadaptor device for enabling a paste or other viscous fluid materialapplicator device, for receiving or including an elongate fluid materialreservoir containing an elongate piston displaceable therein fordisplacing the solder paste or in such fluid material, to be acted uponby the vertically displaceable pressing members of a solder paste orother viscous material screen printing machine, and said adaptor devicecomprising a pressure receiving member locatable on the elongatereservoir or the supporting main body therefor and to be acted upon bythe pressing members of the reciprocating means of a screen printingmachine in a downward direction, and piston displacing means which causethe piston to be displaced downwardly when said pressure receivingmember is acted on by said pressing members to urge solder pastecontained within the reservoir downwardly; the surfaces of said devicewhich are engaged by said pressing members being of or at a height ordisplaceable within a limited range such that, in operation, thedownward displacement of the pressing members of the reciprocating meansof a screen printing machine does not exceed that as may be permitted bythe machine for normal operation without stopping of the machine.
 32. Asolder paste or other viscous material screen printing machine incombination with a paste or viscous material applicator device and anadaptor device in between the reciprocating mechanism for transmittingthe pressing forces of the reciprocating mechanism to the applicatordevice whilst limiting the downward movements of the reciprocatingmechanism to be within acceptable limits, with said adaptor devicecomprising a pressure receiving member and to be acted upon by one ormore pressing members of the reciprocating mechanism of the screenprinting machine in a downward direction, and piston displacing meansbeneath said pressure receiving member which means, in use, isdownwardly displaceable together with the pressure receiving member tocause the piston to be displaced downwardly when said pressure receivingmember is acted on by said pressing members and to urge solder paste orother viscous material contained within the reservoir downwardly, andone-way movement enabling means operatively connecting said pressurereceiving member to said piston displacing means such said one-waymovement enabling means is such as to normally only permit movement ofsaid pressure-receiving member in an upward direction away from saidpressure member; and wherein said pressure-receiving member is biasedaway from said pressing member so as to be displaceable upwardly to itsoriginal position following each downward displacement thereof andrelease.
 33. A combination as claimed in claim 32, in which adjustmentmeans are provided to enable the maximum separation between the pressurereceiving member biased away from the piston displacing means to beadjusted.
 34. A combination as claimed in claim 32 or 33, in which theone-way movement enabling means is a ball-lock device.
 35. A combinationas claimed in any of claims 32 to 34, in which stop means are providedto limit the downward movement of said pressure receiving member to bewithin said acceptable limits so that the printing machine will continueoperation.
 36. An applicator device as claimed in any of claims 1 to 12,in which the main body is elongate and horizontally extending and onwhich the piston is elongate and extends along said reservoir.
 37. In asolder paste or other viscous material printing machine for applyingsolder paste or other material through apertures in a stencil to asubstrate therebeneath for producing printed circuit boards and in whicha reciprocating mechanism is provided for normally hitherto displacingone or more squeegee blades in a horizontal or substantially horizontaldirection and also hitherto for normally effecting vertical orsubstantially vertical displacements of the squeegee blades, theimprovement comprising an applicator device slideable on a stenciltherebeneath and including a reservoir body for containing solder pastehaving an outlet at its lower end for discharge of solder paste or otherviscous material onto a stencil, and said reservoir body being open atits upper end and containing a piston for discharging said solder pasteas it is moved downwards, with said piston being abuttable from aboveand at least downwardly displaceable by mechanical pressure meansmechanically connected to said reciprocating mechanism of the printingmachine and such that in use the applicator device is urged via pressuretransmitted through the solder paste or other material into sealingsliding abutment with said stencil.
 38. In a solder paste or otherviscous material printing machine as claimed in claim 35, wherein anadaptor device is provided between the reciprocating mechanism and theapplicator device and the adaptor device includes a piston pressingmember or includes said piston and a pressure receiving member which isto be acted upon by the upward/downward reciprocating mechanism of themachine and is biased to move away from said piston pressing member orpiston by a predeterminable distance, and a one-way movement enablingdevice only normally permitting movement of said pressure-receivingmember in an upward direction away from said piston pressing member orpiston and wherein with every downward displacement of the pistonpressing member or piston and the pressure-receiving member, solderpaste or other viscous material contained within the reservoir isurgeable downwardly and out of said reservoir, with saidpressure-receiving member being biased away from said piston pressingmember or piston so as to be displaced upwardly to its original positionfollowing each downward displacement thereof, and wherein said adaptordevice is such or adjustable so as to be such or cooperates with theapplicator device which acts as a stop such that the lowermost downwardpermitted movement of the reciprocating mechanism does not exceed thatas may be permitted by the control means of the printing machine withoutstopping of the machine.
 39. An adaptor device as claimed in any ofclaims 1 to 35 or 38, in which means are provided to indicate, in use,the spacings of the pressure receiving member from the piston pressingmember which is representative of the amount of material left in thereservoir.